Ultralong cellulose nanofibers with extremely high aspect ratio were
successfully manufactured from waste corrugated paper pulp through a
series of chemical treatments combined with grinding, ultrasonication,
and centrifugation. SEM images revealed that the prepared cellulose
nanofibers exhibited a uniform width ranging from 30 to 100 nm and a
web-like network structure. The nanopaper was produced by filtration
and oven drying using the obtained cellulose nanofibrils suspension. An
interesting phenomenon occurred, namely that the nanopaper formed in
multilayered nanofibrous flakes, which can be seen in the SEM image of
the nanopaper cross section. The nanopaper derived from waste
corrugated paper presented high tensile properties, with a tensile
strength of 135 MPa and a tensile modulus of 6.67 GPa, which was
approximately 10 times higher than the untreated waste corrugated
paper. The obtained nanopaper also exhibited high transmittance of
85.2% at 600 nm wavelength and low thermal expansion of 16.2 ppm/K.
The high performance nanopaper seems to be a strong candidate for
fabricating optical electronics, solar cells, and panel sensors.